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AbstractAbstract
[en] The electrochemical hydrogen compressor (EHC) is a promising system combining both the purification and compression steps required for the use of hydrogen in devices such as proton exchange membrane fuel cells. Its usage could enable to reduce the price of hydrogen, thus facilitating the popularization of hydrogen-powered devices. However, to be competitive, EHC must sustain large current densities (in the range of 2 A cm-2), an ambitious goal considering the presence of pollutants gases at the anode, where the hydrogen oxidation reaction (HOR) is performed. Therefore, it is essential for the anode electrocatalysts to present a high tolerance towards poisoning impurities such as CO or CO2, as well as very good activity towards the HOR. The present work investigates two families of electrocatalysts with promising properties in those aspects. On the one hand, the Pt+Ru family, composed of unalloyed Pt and Ru nanoparticles deposited on carbon support, presented CO oxidation current at potential values as low as for pure Ru, while keeping a good activity for the HOR when measured in rotating disk electrode (contrary to Ru, that displays poor HOR activity). On the other hand, the WO3-supported Pt and Pt+Ru electrocatalysts displayed good CO-oxidation onset, despite a lower HOR activity and a very poor stability. The most promising electrocatalysts were compared in a gas diffusion electrode (GDE) test cell, in which mass transport limitations are lowered. This enabled the proper comparison of all the electrocatalysts at high current densities, an endeavour to their use in EHC. (author)
[fr]
La pompe electrochimique a hydrogene (EHC en anglais) est un systeme prometteur combinant a la fois les etapes de purification et de compression necessaires a l'utilisation de l'hydrogene dans des dispositifs tels que la pile a combustible a membrane echangeuse de protons. Son utilisation pourrait permettre de reduire le cout de l'hydrogene, facilitant ainsi l'essor des technologies de l'hydrogene. Cependant, l'EHC doit fonctionner a grande densite de courant (de l'ordre de 2 A cm-2) pour etre competitif, un objectif ambitieux si l'on prend en compte la presence de polluants a l'anode, ou la reaction d'oxydation de l'hydrogene (HOR en anglais) a lieu. Les electrocatalyseurs a l'anode doivent donc presenter une grande tolerance aux impuretes comme le CO ou le CO2, ainsi qu'une excellente activite pour l'HOR. Ce travail s'interesse a l'etude de deux familles d'electrocatalyseurs presentant des proprietes interessantes pour ces aspects. D'un cote, la famille Pt+Ru est composee de nanoparticules non-alliees de Pt et Ru, deposees sur un meme substrat carbone. Elles presentent des courants d'oxydation de CO a un potentiel aussi bas que celui de Ru, tout en gardant une bonne activite HOR (mesuree en electrode a disque tournant), contrairement a Ru, qui exhibe une faible activite pour l'HOR. De l'autre cote, les electrocatalyseurs de Pt et Pt+Ru supportes sur WO3 affichent un tres bon debut d'oxydation de CO, malgre une faible activite HOR et une mauvaise stabilite. Les meilleurs electrocatalyseurs sont compares avec une electrode a gaz (GDE), qui permet la reduction des limitations de transports de matiere. Ce montage permet une comparaison plus rigoureuse des electrocatalyseurs a grande densite de courant, plus representative de leur usage en EHC. (auteur)Original Title
Electrocatalyseurs de l'oxydation de l'hydrogene en presence de polluants. Application a la purification/compression de l'hydrogene
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16 Jul 2021; 168 p; 287 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses; These Docteur de l'Universite Grenoble Alpes, Specialite: Materiaux, Mecanique, Genie Civil, Electrochimie
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Miscellaneous
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CARBON COMPOUNDS, CARBON OXIDES, CATALYSTS, CHALCOGENIDES, CHEMICAL ANALYSIS, CHEMICAL REACTIONS, COMPRESSORS, ELECTRODES, ELEMENTS, MATERIALS, METALS, NANOMATERIALS, NONMETALS, OXIDES, OXYGEN COMPOUNDS, PLATINUM METALS, QUANTITATIVE CHEMICAL ANALYSIS, REFRACTORY METAL COMPOUNDS, REFRACTORY METALS, TITRATION, TRANSITION ELEMENT COMPOUNDS, TRANSITION ELEMENTS, TUNGSTEN COMPOUNDS, VOLUMETRIC ANALYSIS
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